Diagnostic Considerations

Pyruvate carboxylase deficiency presents with similar chemical and central nervous system findings as pyruvate dehydrogenase complex deficiency. Enzyme testing is required to distinguish between the two conditions.

Other conditions to consider in the differential diagnosis include the following:

This diagram shows a simplified version of the citric acid cycle and shows the enzyme deficit. The dashed line indicates the blocked pathway and the size of the arrows indicates the relative flow of products. Because pyruvate does not proceed to acetyl-coenzyme A (CoA), it is shunted to other pathways that produce lactic acid and alanine.